Whereas, the increased ANF expression level remained unchanged in STAT3 KO mice (9.37 ± 2.62 fold, P = 0.0476) and revealed a significant higher expression (P = 0.0160) of ANF in cardiac tissue of infected STAT3 KO mice compared to infected WT 28 days after infection (Figure 4). This evidence concerns the gene STAT3 and infection.